Process of sterilizing



J. C. BAKER.

PROCESS OF STERILIZING.

APPLICATION FILED SEPT-13,1919.

Inven or. Jf m C7 4, By Attorney S.

UNITED STATES PATENT. OFFICE.

JOHN G. BAKER, OF RIDGEFIELD PARK, NEW JERSEY.

PROCESS OF STERILIZING.

\ full, clear, and exact description.

It has been proposed and experiments have heretofore been conducted forutilizing nitrogen trichlorid (NCl as a sterilizing agent, but theprocesses followed and the results obtained have led to a very generallyaccepted belief in its uselessness for this purpose. This conclusion, Inow have reason to believe, was largely based upon a fallure to producereal nitrogen tri-chlorid and a failure toproduce what purported to bethis compound in a condition in which it could be practically appliedand used for the purpose.

Nitrogen tri-chlorid as a chemical compound, has been long known, butbecause of the difiiculty of producing it, and because of its explosivecharacter it has not been practicable to make and preserve it for anyuseful purpose. I have discovered, however, that as a sterilizing ordisinfecting agent it has remarkable andvaluable properties, beingnearly as rapidin its action as chlorin, and in cases where a large ormore than the usual amount of chlorin is required to effectsterilization or disinfection, that is to say over 0.1 to 0.3 p. p. m.,it may be used in its stead with great economy and success, In certainwork under my supervision, for example, at Ottawa, Canada, 1.8 p. p. m.of chlorin were required for sterilization, but I accomplished the sameresult with 0.5 p. p. m. of nitrogen trichlorid, thus securing markedeconomy of operation, and I have further found that in certain liquidssuch as sewage or other chlorin consuming liquids, sterilization may beeffected with a much less proportion of nitrogen tri-chlorid than wouldbe required of chlorin.

My discovery that nitrogen tri-chlorid is a valuable and eificientsterilizing agent owes its value and importance, moreover, to a processor method which I have devised for producing and using it, which processinvolves not only a novel manner of making the compound, but itsimmediate application or use for sterilizing, as it may not bepractically accumulated -or stored, and ac- Speeification of LettersPatent.

Patented May 1'7, 1921.

Application filed September 13, 1919. Serial No. 323,650.

cording to my invention I proceed as followsz I dissolve chlorin gas inwater in the proportion of 0,1 to 0.5% of chlorin to water, and passthis aqueous solution through a body of crushed limestone until thechlorin 1s all converted to hypochlorous acid and the hydrochloric acid(HCl) all neutralized. The reaction may be thus expressed:

The first named reaction is reversible, and using the quantitiesspecified does not go to completion, but may be completed by theneutralization of the hydrochloric acid by the action of the limestone.This acid after conversion to weak carbonic acid (H CO -will becomefinally converted'by prolonged contact with the limestone to calciumbicarbonate (Ca (I-IC'O The active material in the resulting solution ishypochlorous acid (HOCl), which is thus obtained free from chlorin (C1,)or hydrochloric acid (HCl), and in concentrat on sufficient foreconomical working condit ons. The solution resulting from this act1onof the limestone is then mixed in measured quantity with ammonia or anysolut1on containing a known quantity of ammonia or ammonium compoundssuch as ammonium hydroxid, chlorid or sulfate or other compound, and themixture results in the formation N01,), as shown by the followingequation:

NILOH 3HOOl-+NC1, e1 0 OI In these equations the proportion by weight ofavailable chlorin to ammonia (NH,,) is 12.5 to 1, and the resultingproduct may be used under proper condition, as I shall hereinafter morefully set forth as a highly useful and eflicient sterilizing agent formany purposes. V

In order that my process may be successfully carried out, I have annexedhereto a drawing which illustrates diagrammatically an apparatus bymeans of which the invention may be practised.

I use containers '1, 1 of chlorin which passes as may be desired orcontrolled to a chlorin meter 2; F rorm there the gas -passes throughacheck valve 3 to an injector 4, by

of nitrogen tri-chlorid means of which it is passed into a regulatedflow of water entering through a valve controlled inlet 5 in a pipe line6 when it combines with the water to form a chlorin solution.

This solution is introduced into a tower or extended chamber orreceptacle 7 containing crushed limestone, and by the action of which itis converted into hypochlorous acid. This latter solution is taken offby a pipe 8, an overflow pipe 9 being provided for use in case of need,and by such pipe it is delivered into a constant level box or chamber10.

' From this latter it is passed in regulated quantity 'into a mixingchamber 11 by a pipe 12, provided with valves and a gage, and enteringthe top of said chamber.

I also use an ammonia tank 13 for con-= taining the ammonia or ammoniumsolution and connect this tank by a pipe 14 with a constant level box orreceptacle15 from which a pipe with valves and a gage to regulate theflow of ammonia leads into the top of the mixing chamber.

To facilitate the mixture of the two in gredients a pipe 16 with a waterjet enters the mixing chamber and the resulting solu-' tion is led offby a pipe 17 to the water, sewage or other materlal which is to besterilized in the ordinary or any well-known manner.

All parts of this apparatus are of wellknown character and 'are widelyused in other. processes, particularly those involving the use ofchlorid as a sterilizing agent.

The resulting solution, if the rates of supply of the hypochlorous acidand ammonia be properly determined and regulated, will contain nitrogentri-chlorid in an aqueous solution, and it may be used for sterilizingwater, milk, sewage, or other articles or materials. The compound isexceedingly .volatile and by spraying or otherwise subdividing thesolution it may be driven off as a gas, and utilized in this conditionas a sterilizmg agent, especially for solid articles, such as fruits andthe like,

I have. not shown any special mechanism 2. The process herein describedof sterilizing which consists in producing ,hypochlorous acld, m1x1ngtherewith ammonia or ammonlum compounds in measured roportions andutilizing the solution of n1trogen-tri-chlorid resulting therefromimmediately as produced as a sterilizing agent.

3. The process. of sterilizing herein described, which consists incontinuously bringing together during the period and at the rate of theuse of the product the materials necessary for producing an aqueoussolution of nitrogen trichlorid, forcing air through the solution asproduced and applying the gas as the sterilizing agent.

4. The process of sterilizing herein described which consists in mixingin meas ured quantities hypochlorous acid and ammonia or ammoniumcompounds and utilizing the nitrogen tri-chlorid resulting from suchmixture immediately. as produced as the sterilizing agent.

In testimony whereof I hereunto aflix my signature. JOHN C. BAKER.

